[Federal Register: June 24, 1999 (Volume 64, Number 121)]
[Proposed Rules]
[Page 33816-33825]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24jn99-23]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
RIN 1018-AF67
Endangered and Threatened Wildlife and Plants; Proposed Rule to
Remove the Northern Populations of the Tidewater Goby From the List of
Endangered and Threatened Wildlife
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
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SUMMARY: The Fish and Wildlife Service, pursuant to the Endangered
Species Act of 1973, as amended (Act), proposes to remove the northern
populations of the tidewater goby (Eucyclogobius newberryi) from the
list of endangered and threatened wildlife. The species is now
classified as endangered throughout its entire range. We have
determined that north of Orange County there are more populations than
were known at the time of the listing, that the threats to those
populations are less severe than previously believed, and that the
tidewater goby has a greater ability than was known in 1994 to
recolonize habitats from which it is temporarily absent. This proposal
would remove the northern populations of the tidewater goby from
protection under the Act.
The Orange and San Diego counties population of tidewater goby,
which constitutes a distinct population segment, is genetically
distinct, is comprised of gobies from only six localities, and
continues to be threatened by habitat loss and degradation, predation
by non-native species, and extreme weather and streamflow conditions.
Therefore, this distinct population segment will be retained as an
endangered species on the List of Endangered and Threatened Wildlife.
DATES: We must receive comments from all interested parties by August
23, 1999. We must receive public hearing requests by August 9, 1999.
ADDRESSES: Send written comments and other materials concerning this
proposal to Ms. Diane Noda, Field Supervisor, Ventura Fish and Wildlife
Office, 2493 Portola Road, Suite B, Ventura, California 93003. You may
inspect comments and materials received, by appointment, during normal
business hours at the above address.
FOR FURTHER INFORMATION CONTACT: Carl Benz at the above address;
telephone 805/644-1766, facsimile 805/644-3958.
SUPPLEMENTARY INFORMATION:
Background
The tidewater goby was first described in 1857 by Girard as Gobius
newberryi. Gill (1862) erected the genus Eucyclogobius for this
distinctive species. The majority of scientists has accepted this
classification (e.g., Bailey et al. 1970, Miller and Lea 1972, Hubbs et
al. 1979, Robins et al. 1991, Eschmeyer et al. 1983). No other species
has been described in this genus. A few older works and Ginsburg (1945)
placed the tidewater goby and the eight related eastern Pacific species
into the genus Lepidogobius. This classification includes the currently
recognized genera Lepidogobius, Clevelandia, Ilypnus, Quietula, and
Eucyclogobius. Birdsong et al. (1988) coined the informal Chasmichthys
species group, recognizing the phyletic relationship of the eastern
Pacific group with species in the northwestern Pacific.
Crabtree's (1985) allozyme work on tidewater gobies from 12
localities throughout the range shows fixed allelic differences at the
extreme northern (Lake Earl, Humboldt Bay) and southern (Canada de Agua
Caliente, Winchester Canyon, and San Onofre Lagoon) ends of the range.
The northern and southern populations are genetically distinct from
each other and from the central populations sampled. The more centrally
distributed populations are relatively similar to each other (Brush
Creek, Estero Americano, Corcoran Lagoon, Arroyo de Corral, Morro Bay,
Santa Ynez River, and Jalama Creek). Crabtree's results indicate that
there is a low level of gene flow (movement of individuals) between the
populations sampled in the northern, central, and southern parts of the
range. However, Lafferty et al. (in prep.) point out that Crabtree's
sites were widely distributed geographically, and may not be
[[Page 33817]]
indicative of gene flow on more local levels.
Recently, David Jacobs (University of California, Los Angeles,
Department of Organismic Biology, Ecology and Evolution, in litt.,
1998) initiated an analysis of mitochondrial genetic material from
tidewater goby populations ranging from Humboldt to San Diego counties.
Preliminary results indicate the San Diego gobies separated from other
gobies along the coast long ago. These southernmost populations likely
began diverging from the remainder of the gobies in excess of 100,000
years ago. Furthermore, gobies from the Point Conception area are more
closely related to gobies from Humboldt County than they are to the
gobies analyzed in San Diego County.
The tidewater goby (Eucyclogobius newberryi) is a small, elongate,
grey-brown fish with dusky fins not exceeding 50 millimeters (mm) (2
inches (in.)) standard length (SL). The tidewater goby is a short-lived
species, apparently having an annual life cycle (Irwin and Soltz 1984,
Swift et al. 1997). At the time of the listing, the species was
believed to have more stringent habitat requirements and to be less
likely to disperse successfully than recent research indicates (see
below). These factors, coupled with the short life span of the
tidewater goby, were believed to make most tidewater goby populations
vulnerable to extirpation by human activities. At the time of the
listing, we believed that approximately 50 percent of the documented
populations had been extirpated. However, in spite of the many factors
affecting coastal wetlands, recent survey data demonstrate a less than
25 percent permanent loss of the known tidewater goby populations
(Ambrose et al. 1993; Swift et al. 1994; Lafferty et al. 1996; C.
Chamberlain, U.S. Fish and Wildlife Service, Arcata, California, in
litt. 1997; Lafferty 1997; Swift et al. 1997).
The tidewater goby inhabits coastal brackish water habitats
entirely within California. Within the range of the tidewater goby,
these conditions occur in two relatively distinct situations: (1) The
upper edge of tidal bays, such as Tomales, Bolinas, and San Francisco
bays near the entrance of freshwater tributaries, and (2) the coastal
lagoons formed at the mouths of small to large coastal rivers, streams,
or seasonally wet canyons, along most of the length of California. Few
well authenticated records of this species are known from marine
environments outside of enclosed coastal lagoons and estuaries (Swift
et al. 1989). This may be due to the lack of collection efforts at
appropriate times (i.e., following storm events or breachings when
gobies are flushed from the estuaries and lagoons). Historically, the
species ranged from Tillas Slough (mouth of the Smith River, Del Norte
County) near the Oregon border to Agua Hedionda Lagoon (northern San
Diego County).
The tidewater goby is often found in waters of relatively low
salinities (around 10 parts per thousand (ppt)) in the uppermost
brackish zone of larger estuaries and coastal lagoons. However, the
fish can tolerate a wide range of salinities (Swift et al. 1989, 1997;
Worcester 1992; K. R. Worcester, California Department of Fish and Game
(CDFG), in litt. 1996; Worcester and Lea 1996), and is frequently found
throughout lagoons. Tidewater gobies regularly range upstream into
fresh water, and downstream into water of up to 28 ppt salinity
(Worcester 1992, Swenson 1995), although specimens have been collected
at salinities as high as 42 ppt (Swift et al. 1989). The species'
tolerance of high salinities (up to 60 ppt for varying time periods)
likely enables it to withstand the marine environment, allowing it to
colonize or re-establish in lagoons and estuaries following flood
events (Swift et al. 1989; K. R. Worcester, in litt. 1996; Worcester
and Lea 1996; Lafferty et al. in prep.).
Tidewater gobies are usually collected in water less than 1 meter
(m) (3 feet (ft)) deep; many localities have little or no area deeper
than this (Wang 1982, Irwin and Soltz 1984, Swift et al. 1989, Swenson
1995). However, it has been found in waters over 1 m in depth
(Worcester 1992, Lafferty and Altstatt 1995, Swift et al. 1997, Smith
1998). In lagoons and estuaries with deeper water, the failure to
collect gobies may be due to the inadequacy of the sampling methods,
rather than the lack of gobies (Worcester 1992, Lafferty 1997, Smith
1998).
Tidewater gobies often migrate upstream into tributaries up to 2.0
kilometers (km) (1.2 mile (mi)) from the estuary. However, in San
Antonio Creek and the Santa Ynez River, Santa Barbara County, tidewater
gobies are often collected 5 to 8 km (3 to 5 mi) upstream of the tidal
or lagoonal areas, sometimes in beaver impounded sections of streams
(Swift et al. 1989). The fish move upstream in summer and fall, as sub-
adults and adults. There is little evidence of reproduction in these
upper areas (Swift et al. 1997).
Populations originally inhabiting tidal areas, such as those found
in San Francisco Bay, rarely were studied before they disappeared, and
none remain to adequately study their use of truly tidal conditions.
Several of the lagoonal habitats have been converted by human
activities into tidal harbors and bays, such as Humboldt Bay, Elkhorn
Slough, Morro Bay and Santa Margarita River, among others (Swift et al.
1989, 1993). Populations recently present in these artificially created
tidal situations, such as Elkhorn Slough, Morro Bay, and Santa
Margarita River, have disappeared in the last 5 to 10 years. The only
remaining tidal system with tidewater gobies is Humboldt Bay (Swift et
al. 1989; C. Chamberlain, in litt. 1997).
The life history of tidewater gobies is keyed to the annual cycles
of the coastal lagoons and estuaries (Swift et al. 1989, 1994; Swenson
1994, 1995). Water in estuaries, lagoons and bays is at its lowest
salinity during the winter and spring as a result of precipitation and
runoff. During this time, high runoffs cause the sandbars at the mouths
of the lagoons to breach, allowing mixing of the relatively fresh
estuarine and lagoon waters with seawater. This annual building and
breaching of the sandbars is part of the normal dynamics of the systems
in which the tidewater goby has evolved (e.g., Zedler 1982, Lafferty
and Alstatt 1995, Heasly et al. 1997). The time of sandbar closure
varies greatly between systems and years, and typically occurs from
spring to late summer. Later in the year, occasional waves washing over
the sandbars can introduce some sea water, but good mixing often keeps
the lagoon water at a few parts per thousand salinity or less. Summer
salinity in the lagoon depends upon the amount of freshwater inflow at
the time of sandbar formation (Zedler 1982, Heasly et al. 1997).
Males begin digging breeding burrows 75-100 mm (3-4 in.) deep,
usually in relatively unconsolidated, clean, coarse sand averaging 0.5
mm (0.02 in.) in diameter, in April or May (Swift et al. 1989; Swenson
1994, 1995). Swenson (1995) has shown that tidewater gobies prefer this
substrate in the laboratory, but also found tidewater gobies digging
breeding burrows in mud in the wild (Swenson 1994). Inter-burrow
distances range from about 5 to 275 centimeters (cm) (2 to 110 in.)
(Swenson 1995). Females lay about 100-1000 eggs per clutch, averaging
400 eggs/clutch, with clutch size depending on the size of both the
female and the male. Females can lay more than one clutch of eggs over
their lifespan, with captive females spawning 6-12 times (Swenson
1995). Wild females may spawn less frequently due to fluctuations in
food supply and other environmental conditions, but the species clearly
has a high reproductive potential, enabling populations to recover
quickly under suitable conditions. Male gobies remain in the
[[Page 33818]]
burrow to guard the eggs that are attached to sand grains in the walls
of the burrow. Males also spawn more than once per season (Swenson
1995), and although they can have more than one clutch in their burrow,
presumably from different females (Swift et al. 1989), Swenson (1995)
found that males accepted only one female per brood period. Males
frequently go for at least a few weeks without feeding, and this
probably contributes to a mid-summer mortality often noted in
populations (Swift et al. 1989; Swenson 1994, 1995).
Reproduction peaks during spring to mid-summer, late April or May
to July, and can continue into November or December depending on the
seasonal temperature and rainfall. Reproduction sometimes increases
slightly in the fall (Swift et al. 1989; Camm Swift, Department of
Biology, Loyola Marymount University, pers. comm., 1995). Reproduction
takes place from 15-20 degrees Celsius<Copyright> (60-65 degrees
Fahrenheit (F)) and at salinities of 0-25 ppt (Swift et al. 1989;
Swenson 1994, 1995). Typically, winter rains and cold weather interrupt
spawning, but in some warm years reproduction may occur all year
(Goldberg 1977, Wang 1984). Goldberg (1977) showed by histological
analysis that females have the potential to lay eggs all year in
southern California, but this rarely has been documented. Length-
frequency data from southern and central California (Swift et al. 1989;
Swenson 1994, 1995) and analysis of otoliths from central California
populations (Swift et al. 1997) indicate that tidewater gobies are an
annual species and typically live one year or less.
Tidewater goby eggs hatch in 7-10 days at temperatures of 15-18
degrees C (60-65 degrees F). The newly hatched larvae are 4-7 mm (0.2
in) in length and are planktonic for one to a few days. Once they reach
8-18 mm (0.3-0.8 in.) in length they become substrate oriented. All
larger size classes are substrate oriented and, although little habitat
segregation by size has been noted (Swift et al. 1989, Swenson 1995),
Worcester (1992) did find that larval gobies in Pico Creek Lagoon
tended to use the deeper portion of the lagoon. Individuals collected
in marshes appear to be larger (43-45 mm (1.7-1.8 in.) SL) than those
collected in open areas of lagoons (32-35 mm (1.3-1.4 in.) SL) (Swenson
1995).
Studies of the tidewater goby's feeding habits suggest that it is a
generalist. At all sizes examined, tidewater gobies feed on small
invertebrates, usually mysids, amphipods, ostracods, snails, and
aquatic insect larvae, particularly dipterans (Irwin and Soltz 1984;
Swift et al. 1989; Swenson 1994, 1995). The food items of the smallest
tidewater gobies (4-8 mm (0.2-0.3 in.)) have not been examined, but
these gobies, like many other early stage larval fishes, probably feed
on unicellular phytoplankton or zooplankton (Swenson and McCray 1996).
Tidewater gobies may be preyed upon by native species such as
steelhead (Oncorhynchus mykiss) (Swift et al. 1989), and are documented
prey items of prickly sculpin (Cottus asper), staghorn sculpin
(Leptocottus armatus), and starry flounder (Platichthys californicus)
(Swift et al. 1997). However, tidewater gobies were found in stomachs
of only 6 percent of nearly 120 of the latter three species examined,
and comprised less than 20 percent by volume of the prey. Predation by
the Sacramento perch (Archoplites interruptus) and tule perch
(Hysterocarpus traski) may have prevented tidewater gobies from
inhabiting the San Francisco Bay delta (Swift et al. 1989), although
direct documentation to support this hypothesis is lacking.
Tidewater gobies also are preyed upon by non-native African clawed
frogs (Xenopus laevis) (Lafferty and Page 1997), although this is
probably not a significant source of mortality due to the limited
distribution of this frog species in tidewater goby habitats. The frogs
are killed by the higher salinities that occur when the lagoons are
breached (Glenn Greenwald, U.S. Fish and Wildlife Service, pers. obs.).
Several non-native fish species also prey on tidewater gobies. The
shimofuri goby (Tridentiger bifasciatus), which has become established
in the San Francisco Bay region (Matern and Fleming 1995), may compete
with the smaller tidewater goby, based on dietary overlap (Swenson
1995) and foraging and reproductive behavioral observations in
captivity. Shimofuri gobies have been observed to eat juvenile
tidewater gobies in captivity, but usually were unable to catch
subadult and adult tidewater gobies (Swenson and Matern 1995). Evidence
of predation or competition in the wild is lacking (Swenson 1998).
Competition with yellowfin (Acanthogobius flavimanus) and chameleon
(Tridentiger trigonocephalus) gobies has also been hypothesized.
Although Wang (1984) found that yellowfin gobies do prey on tidewater
gobies, no data were presented indicating the extent of such
interactions, nor has there been any further documentation of such
competitive or predatory interactions with either species. Shapovalov
and Taft (1954) documented the non-native striped bass (Morone
saxatilis) preying on tidewater gobies in Waddell Creek Lagoon, but
stated that striped bass were found only infrequently in the areas
inhabited by the goby. Sunfishes and black bass (Centrarchidae) have
been introduced in or near coastal lagoons and may prey heavily on
tidewater gobies under some conditions. Predation by young-of-the-year
largemouth bass (Micropterus salmoides) on tidewater gobies was
documented in one system (Santa Ynez River), where tidewater gobies
accounted for 61 percent of the prey volume of 55 percent (10 of 18) of
the juvenile bass sampled (Swift et al. 1997). Although tidewater
gobies disappeared soon after centrarchids were introduced at several
localities, direct evidence that the introductions led to the
extirpations is lacking (Swift et al. 1989, 1994; Rathbun et al. 1991;
Dan Holland, Department of Biology, Southwestern Louisiana State
University, Monroe, LA, pers. comm. 1991). In at least one location,
tidewater gobies have re-established naturally (see below).
Lafferty et al. (1996) monitored post-flood persistence of 17
tidewater goby populations in Santa Barbara and Los Angeles counties
during and after the heavy winter flows of 1995. All 17 populations
persisted after the high flows, and no significant changes in
population sizes were detected. In addition, gobies apparently
colonized Canada Honda, approximately 10 km (6 mi) from the closest
known population, during or after the flooding (Swift et al. 1997).
Lafferty et al. (in prep.) estimated the extirpation and recolonization
rates for 37 populations in southern California, based on over 250
presence-absence records. They found higher recolonization rates than
expected, and suggested that there is more gene flow among populations
within geographic clusters (northern California, San Francisco Bay,
Santa Cruz, San Luis Obispo and south) than previously believed to
exist. They also found an association between tidewater goby presence
and wet years. This information suggests that flooding may contribute
to recolonization of sites from which gobies have temporarily
disappeared.
Lagoons in which tidewater gobies are found range in size from a
few square meters (yards) (less than 0.10 hectares (ha) (0.25 acres
(ac)) of surface area to about 800 ha (2000 ac). Most lagoons with
tidewater goby populations are in the range of 0.5-5 ha (1.25-12.5 ac).
Surveys of tidewater goby localities and historical records indicate
that size,
[[Page 33819]]
configuration, location, and access by humans are all related to
persistence of populations of this species (Swift et al. 1989, 1994).
Watered surface areas smaller than about 2 ha (5 ac) generally have
histories of extinction, extirpation, or population reduction to very
low levels, although some as small as 0.35 ha (0.86 ac) have been
identified as having permanent tidewater goby populations (Swift et al.
1997, Lafferty 1997, Heasly et al. 1997). As evidenced by the Canada
Honda colonization (Swift et al. 1997), even relatively long distances
are not obstacles to colonization or re-establishment. Many of the
small lagoons with histories of intermittent populations are within 1-2
km (0.6-1.2 mi) of larger lagoons that can act as sources of colonizing
gobies.
The largest localities have not proved to be the best for the
species, as evidenced by the loss of tidewater gobies from San
Francisco and Morro bays and the Santa Margarita River estuary. Today,
the most stable and largest populations are in lagoons and estuaries of
intermediate sizes, 2-50 ha (5-125 ac) that have remained relatively
unaffected by human activities, although some systems that are heavily
affected or altered also have large, stable populations (e.g., Santa
Clara River, Ventura County; Santa Ynez River, Santa Barbara County;
Pismo Creek, San Luis Obispo County). In many cases these probably have
provided the colonists for the smaller ephemeral sites (Swift et al.
1997, Lafferty et al. in prep.).
Distinct Population Segments
We analyzed tidewater goby populations based on the joint National
Marine Fisheries Service and U.S. Fish and Wildlife Service Policy
Regarding the Recognition of Distinct Vertebrate Populations, published
in the Federal Register on February 7, 1996 (61 FR 4722). We consider
three elements in determining whether a vertebrate population segment
could be treated as threatened or endangered under the Act:
discreteness, significance, and conservation status in relation to the
standards for listing. Discreteness refers to the isolation of a
population from other members of the species and is based on two
criteria: (1) Marked separation from other populations of the same
taxon resulting from physical, physiological, ecological, or behavioral
factors, including genetic discontinuity, or (2) populations delimited
by international boundaries. We determine significance either by the
importance or contribution, or both, of a discrete population to the
species throughout its range. The policy lists four examples of factors
that may be used to determine significance:
(1) Persistence of the discrete population segment in an ecological
setting unusual or unique for the taxon;
(2) Evidence that loss of the discrete population segment would
result in a significant gap in the range of the taxon;
(3) Evidence that the discrete population segment represents the
only surviving natural occurrence of the taxon that may be more
abundant elsewhere as an introduced population outside its historic
range; and
(4) Evidence that the discrete population segment differs markedly
from other populations of the taxon in its genetic characteristics.
If we determine that a population segment is discrete and
significant, we evaluate it for endangered or threatened status based
on the Act's standards.
The previously discussed electrophoretic and mitochondrial DNA
analysis indicates the Orange and San Diego counties population is
genetically discontinuous from other coastal populations of tidewater
gobies. Furthermore, the significant distance (129 km, 80 mi) between
the Orange and San Diego counties population and the closest extant
population physically isolates these gobies from those populations to
the north. Therefore, we conclude the Orange and San Diego counties
population of tidewater gobies is discrete in accordance with our
distinct vertebrate populations policy.
Genetic investigations (e.g., Jacobs in litt., 1998) indicate that
tidewater gobies are made up of four geographically distinct
populations in California. Of these four, the southernmost, in Orange
and San Diego counties, constitutes the most genetically divergent
population. The genetic data reveal differences in the southern
population that are consistent with interspecific boundaries in other
species, and suggest divergence of the southern population from the
rest of the populations over 100,000 years ago. This coincides with the
fact that the southern population is the most geographically isolated,
being 129 km (80 mi) from the nearest extant population. Loss of the
Orange and San Diego counties population of tidewater gobies would
result in a loss of a genetically unique tidewater goby population, and
a reduction in range of tidewater gobies by approximately 129 km (80
mi). We therefore conclude that the Orange and San Diego counties
population is significant in accordance with our distinct vertebrate
populations policy. This population constitutes a distinct population
segment, and we have evaluated it for endangered or threatened status
based on the Act's standards.
Previous Federal Actions
We first classified the tidewater goby as a category 2 species in
1982 (47 FR 58454). We reclassified it as a category 1 candidate in
1991 (56 FR 58804) based on status and threat information in Swift et
al. (1989). Category 2 applied to taxa for which information we
possessed indicated that proposing to list as endangered or threatened
was possibly appropriate, but for which conclusive data on biological
vulnerability and threats were not currently available to support a
listing proposal. Category 1 species, now referred to as candidate
species, applies to taxa for which we have on file substantial
information on biological vulnerability and threats to support a
proposal to list as threatened or endangered. On October 24, 1990, we
received a petition from Dr. Camm Swift, Associate Curator of Fishes at
the Los Angeles Museum of Natural History, to list the tidewater goby
as endangered. We published a finding that the requested action may be
warranted on March 22, 1991. We published a proposal to list the
tidewater goby as an endangered species on December 11, 1992 (57 FR
58770). On March 7, 1994, we listed tidewater goby as a federally
endangered species (59 FR 5494). No critical habitat was designated.
Federal involvement with the tidewater goby following listing has
included consultations under section 7 of the Act, permitting of
breaching and other activities in lagoons through the section 404
process by the U.S. Army Corps of Engineers (ACOE), and funding and
conducting research and surveys. Measures to reduce impacts to
tidewater goby habitat and reduce or eliminate the potential for take
of individuals have included adjusting the timing of projects to avoid
disruption to breeding activities, the use of silt fencing to reduce
sediment loads and as barricades around project sites, installing
coffer dams above and below project sites and removal and translocation
of animals found within the exclosures prior to necessary dewatering of
project sites, minimization of project area, and requiring qualified
biologists to oversee all activities.
Tidewater Goby Status Review
At the time of listing (1994), California had recently experienced
5 years of drought conditions (1987-1991), and we believed that most
populations throughout the species' range were threatened by one or
more factors, including modification and loss
[[Page 33820]]
of habitat as a result of coastal development, channelization of
habitat, diversion and alteration of water flows, groundwater
overdrafting, discharge of agricultural and sewage effluents,
introduction of exotic fish species (particularly centrarchid species),
and increased sedimentation due to cattle grazing and feral pig
activity (59 FR 5494). We have assembled and evaluated new information
regarding habitat status, habitat requirements of the goby, critical
life history needs, dispersal processes and goby population status
during drought and wet years. In the remainder of this section and in
the Summary of Factors Affecting this Species, we review this new
information and reassess the threats to the tidewater goby.
At the time of listing, we believed that the number of extant
tidewater goby populations was 46, with 87 known historically. Since
the listing, 4 populations once believed permanently extirpated have
been rediscovered, 2 populations have been re-established artificially
(Waddell Creek, Malibu Creek), records for at least 15 populations
indicate that they are naturally intermittent, 11 populations believed
extinct due to drought conditions have re-established naturally, and 20
new populations have been found. At present the number of extant
populations is believed to be about 85, and the number of historical
populations about 110.
In the early 1990s, the number of tidewater goby populations
believed to be extinct caused concern, especially considering the high
proportion believed lost in the southern third of the species' range.
The final rule for the listing of the tidewater goby stated that 74
percent of the populations in coastal lagoons south of Morro Bay had
been extirpated, with only 3 populations remaining south of Ventura
County. We now know of 6 populations south of Ventura County, and only
about 20 percent of populations south of Morro Bay are currently
considered extirpated. Range-wide, of the 25 populations currently
considered permanently extirpated, 19 were extirpated prior to 1970,
before regulations protecting the environment were promulgated. The six
more recent population extirpations are discussed in the appropriate
sections below.
Summary of Factors Affecting the Species
Section 4 of the Endangered Species Act and regulations (50 CFR
Part 424) promulgated to implement the listing provisions of the Act,
set forth the procedures for listing, reclassifying, and delisting
species on Federal lists. A species may be determined to be an
endangered or threatened species due to one or more of the five factors
described in section 4(a)(1). A species may be delisted, according to
section 4 regulations (50 CFR Part 424.11(d)), if the best scientific
and commercial data available substantiate that the species is neither
endangered nor threatened because of (1) extinction, (2) recovery, or
(3) original data for classification of the species were in error.
In the case of the tidewater goby, a significant number of
populations previously believed extirpated have recolonized naturally,
and a significant number of populations previously believed to be in
decline have stabilized or increased in size since the listing.
Therefore, we reevaluated all of the factors believed to be threatening
the existence of the tidewater goby. We found that some of our
interpretations of the data available when the species was listed were
in error, and we also found that new information exists which supports
interpretations of status and threats that differ from those presented
in the final listing rule. After a thorough review of all available
information, including considerable new information, we have determined
that, north of Orange and San Diego counties, the tidewater goby is not
endangered or threatened with endangerment. In this part of the range
we now know that there are more populations than were known at the time
of the listing, that the threats to those populations are less severe
than previously believed, and that the tidewater goby has a marked
ability to recolonize habitats from which it is temporarily absent. The
1994 final rule identified several threats to the tidewater goby,
including coastal development, upstream water diversions and alteration
of flows, groundwater overdrafting, discharge of agricultural and
sewage effluents, channelization, cattle grazing, feral pig activity,
predation by introduced fish species, inadequacy of existing regulatory
mechanisms, drought, flood events and competition with introduced
species. A reanalysis of these threats follows.
The remaining tidewater gobies in Orange and San Diego counties,
which constitute a distinct population segment, are limited to the U.S.
Marine Corps Base, Camp Pendleton. Threats to these southernmost
tidewater goby populations differ from those found elsewhere on the
California coast or, due to the small number of populations or other
factors, threats that are minor to the northern populations of gobies
are greatly exacerbated in the south. Urban development, although
possibly impacting recovery areas, is not an overriding threat on Camp
Pendleton. Nevertheless, habitat loss and degradation have occurred
frequently and continue to threaten this population segment, as do
predation by and competition with introduced species. These factors are
discussed below for both the populations north of Orange and San Diego
counties and the population within Orange and San Diego counties.
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
Populations North of Orange and San Diego Counties. Coastal
development projects that result in the loss of coastal saltmarsh
habitat were identified in the final rule as the major threat adversely
affecting the tidewater goby. Such projects probably were the most
significant threat responsible for the historical loss of tidewater
goby populations. Projects included dredging of waterways for
navigation and harbors and road construction that severed the
connections of marshes with the Pacific Ocean. Reevaluation of the
number of extirpations resulting from coastal development and habitat
modification and loss shows that the potential for the substantial
habitat loss and modification that occurred historically has been
reduced substantially. This is due largely to the implementation of key
environmental regulations required by the Clean Water Act, Coastal Zone
Management Act and related California environmental statutes. For
example, only five permanent extirpations resulting from destruction or
modification of habitat have occurred since the initial promulgation of
environmental regulations during the early 1970s (two due to
construction of golf courses, one due to installment of culverts that
altered natural lagoon dynamics, one due to placement of riprap cutting
off ocean access, and one due to water appropriations). Thus, in the
northern part of the species' range (i.e., north of Orange and San
Diego counties) there is insufficient evidence to suggest that
destruction and modification of habitat from coastal development are
occurring at levels that constitute a substantial threat to the
continued existence of the northern populations of tidewater gobies.
We stated in the final rule that upstream water diversions and
groundwater overdrafting may adversely affect the tidewater goby by
altering downstream flows, thereby diminishing the extent of marsh
habitats that occurred historically at the mouths of
[[Page 33821]]
most rivers and creeks and potentially affecting the species' breeding
and foraging activities. The final rule also suggested that alterations
of flows upstream of coastal lagoons resulting in changes in downstream
salinity regimes might affect the tidewater goby due to its presumed
narrow salinity tolerances. Supporting these arguments at the time of
the listing, the population in San Antonio Creek, Santa Barbara County,
was believed to have been extirpated due to groundwater overdrafting.
However, gobies are not currently extirpated from this location; they
were found there in 1995.
Tidewater gobies have been collected from waters ranging from 0 to
42 ppt salinity (Swift et al. 1989, Lafferty and Alstatt 1995). During
the late 1980s and early 1990s, Worcester (1992) conducted an
investigation of habitat use in Pico Creek lagoon, and observed large
numbers of tidewater gobies using the lower portion of the lagoon where
high salinities (up to 27 ppt) were documented. Since the listing,
Swenson (1995) and Swift et al. (1997) have reported capturing gobies
in waters up to 28 ppt and 32 ppt salinity, respectively. Two salinity
tolerance experiments discussed in Swift et al. (1989) indicate that
tidewater gobies can withstand a wide range of salinities, from 0-40
ppt for up to 25 days with 20 percent or less mortality, even when
moved directly from low salinity environments into high. A third
experiment allowed salinities to increase through evaporation for 53
days. At a final salinity of 25 ppt, 75 percent of the tidewater gobies
survived, while 59 percent of those held in water reaching a final
salinity of 62 ppt survived. In the early 1990s, while tidewater gobies
were held at the Granite Canyon Fish Culture Facility, a salinity
tolerance test was conducted in hypersaline water (45-54 ppt) for 6
months, with no mortality. In addition, tidewater gobies were
maintained in fresh water and salinities of 10-15 ppt, 20 ppt, and
normal sea water (about 33 ppt salinity). Reproduction took place in
all four regimes. Some of the laboratory bred tidewater gobies spawned
when they matured (K. R. Worcester, in litt. 1996; Worcester and Lea
1996). Based on these studies, the goby appears tolerant of a broad
range of salinity conditions.
Channelization was identified as a threat in ``most'' of the
habitats occupied by the species due to the scouring effects of high
winter flows in the restricted channels and the lack of protective
habitat. However, with the exception of the extirpation of the Waddell
Creek, Santa Cruz County, population during the winter of 1972-73
attributed to channelization, further review of causes of extirpations
since 1970 has not been able to identify population extirpation due to
this threat. Moreover, tidewater gobies were re-established in Waddell
Creek in 1991 and have persisted there through 1997 (Smith 1998).
Siltation from topsoil runoff and the increased sedimentation and
habitat degradation associated with cattle grazing and feral pig
activity were also identified as threats to the tidewater goby. Many
tidewater goby populations exist in habitats where such agricultural
effluent and runoff and wastewater effluent occur, and the final rule
identified the resulting algal blooms and deoxygenation as possible
factors in the further degradation of tidewater goby habitats. During
the 1950s, sewage effluents high in ammonia were discharged into the
Salinas River and are believed to have been a factor in the apparent
extirpation of that tidewater goby population (Jerry J. Smith, Ph.D.,
San Jose State University, pers. comm. 1998). However, in many lagoons
receiving agricultural and sewage effluents, tidewater gobies are the
most abundant fish species present, as found during surveys of lagoons
in Santa Barbara County (Ambrose et al. 1993). Field observations made
during tidewater goby surveys have found extremely low levels of
dissolved oxygen (0.2-1.7 mg/l) (Worcester1992, Swift et al. 1997) and
elevated temperatures (greater than 30 degrees C) where gobies were
found in high numbers (C. Chamberlain, pers. comm. 1996; E. Ballard,
U.S. Fish and Wildlife Service, Sacramento, California, personal
observation 1997). Based on those observations, the tidewater goby
appears to be tolerant of agricultural and sewage effluents, and of a
wide range of dissolved oxygen levels and temperatures.
We suggested in the final rule that only 6 to 8 of the 46 remaining
populations were large enough and free enough from habitat degradation
to be safe in the immediate future. The remaining lagoons were
considered so small or modified that tidewater goby populations were
thought to be restricted in distribution and vulnerable to extirpation.
Of particular concern was the extirpation of smaller populations due to
effects of drought exacerbated by upstream water diversions. The number
of extirpated populations of gobies was believed to leave remaining
populations so widely separated throughout most of the species' range
that recolonization was unlikely. New information and analyses indicate
that the tidewater goby is very well adapted to the climatically
dynamic system within which it has evolved, and that the intermittent
occupancy of some sites is a normal aspect of the species' biology
(Swift et al. 1994, 1997; Lafferty et al. in prep.; J. Smith, pers.
comm. 1998). Following the listing of the tidewater goby and the end of
the 1987-1992 drought, at least 14 populations considered extirpated
due to the drought and other causes were found to be extant. In some
cases, these habitats were documented as being dry during the drought,
with no gobies believed to be present in the drainages (e.g., Laguna
and Moore creeks, Santa Cruz County; Arroyo del Puerto, San Luis Obispo
County). Following a return to normal or above average rainfall, gobies
were found not only in those 14 sites but also in approximately 20
others from which they previously had not been found. These findings
show that recolonization is possible and indicate that it is a normal
process following habitat variation due to climatic fluctuations (Swift
et al. 1994, 1997; Lafferty et al. in prep.; J. Smith, pers. comm.
1998).
In a number of cases, surveys that concluded that populations were
extirpated from localities that did not go dry during the drought
apparently were inadequate to determine presence or absence of the
species. Periodic disappearances and re-appearances of the tidewater
goby in various locations during the last 25 years (Lafferty 1997,
Lafferty et al. in prep.) suggest that conclusions regarding presence/
absence based on standard survey methods may not be reliable.
Researchers along the central California coast have observed periods
when tidewater gobies cannot be found, but then later reappear (Rathbun
et al. 1991; Swift et al. 1993, 1997; J. Smith, pers. comm. 1998).
These observations may be the result of the gobies being temporarily
absent from the sampled habitat or the population decreasing
temporarily to a size not detectable by standard presence/absence
methods (e.g., seine hauls). Regardless, the reappearance of tidewater
gobies in localities where they previously were considered to be
extirpated may be the result of earlier surveys being conducted during
the windows of time when gobies temporarily were not observable (Smith
1998; Norm Scott, Ph.D., U.S. Geological Survey, Biological Resources
Division, San Simeon, pers. comm. 1997). The continued survival of
tidewater goby populations, both large and small, following the long
drought of the late 1980s and early 1990s suggests that the previous
assessment that most of the
[[Page 33822]]
populations are extremely vulnerable to extirpation is not valid.
Although not discussed in the final listing rule, artificial lagoon
breaching during the dry season has been suggested as a potential
threat to tidewater gobies. No data exist to substantiate the severity
of this threat (but see the adverse effects of artificial breaching San
Onofre Creek lagoon, below). Significant decreases in water level,
exposure of tidewater goby breeding burrows and bottom habitat, and
increased salinity resulting from breaching during the dry season are
factors that we considered as possible threats to the persistence of
tidewater goby populations. However, in the northern part of its range,
the species continues to persist at numerous locations (e.g., Pescadero
Creek, San Mateo County; Pismo Creek, San Luis Obispo County; Santa
Ynez and Arroyo Burro, Santa Barbara County; Santa Clara River, Ventura
County) where unseasonal breaching occurred on a regular basis prior to
the listing (Swenson 1995; Lafferty 1995; Lafferty and Alstatt 1995;
Heasly et al. 1997; D. W. Alley, in litt. 1998). The lack of any
records of breaching-related extirpations leads us to conclude that
breaching does not pose a significant threat to the northern
populations of the species.
Orange and San Diego Counties Population. Of the 13 historic and
current sites in Orange and San Diego counties, the two northernmost,
Aliso and San Juan creeks in Orange County were lost in the 1980s and
1960s (respectively). The three southernmost sites, San Luis Rey, Buena
Vista, and Agua Hedionda were lost in the 1940s and 1950s. More
recently, it appears that Santa Margarita River, which probably was
habitat for a naturally intermittent population (see Lafferty 1997,
Lafferty et al. in prep.), is now permanently unsuitable due to exotic
species and hydrologic changes. Permanent population losses, such as
those listed above, can seriously influence metapopulation dynamics in
the region, leading to larger scale extinctions, by reducing
opportunities for recolonization of suitable sites. Exacerbating this
concern, recent human activities have further endangered the two
largest goby populations in Orange and San Diego counties (San Onofre
Creek Lagoon, San Mateo Creek Lagoon) which may be important sources of
dispersing gobies that repopulate other areas when they are
periodically lost.
In October 1996, a survey conducted by Drs. Dan Holland and Camm
Swift in the San Onofre Creek lagoon estimated the population of gobies
at 12,265. On November 22, 1996, the lagoon was artificially breached
and water immediately began draining from the lagoon into the ocean.
The water level dropped 40 to 50 cm and the surface area of the lagoon
decreased approximately 60 to 75 percent during the next 12 hours.
During the night of November 22-23, 1996, the bar across the mouth of
the lagoon reformed and water ceased to flow directly into the Pacific
Ocean. On November 24, 1996, Drs. Holland and Swift resurveyed the
lagoon and estimated the goby population at 5,345, a decrease of 6,920
fish from their October 1996 survey (Swift and Holland 1998). Recent
surveys confirm that tidewater gobies are still present in San Onofre
Creek Lagoon but no precise population estimates are available.
On February 24, 1998, repair work began on storm-damaged railroad
trestles that traverse San Mateo Creek Lagoon. This work included
dredging portions of the creek and lagoon, and filling fresh water
marsh which function as goby refugia. The San Mateo goby population at
this locality was estimated at approximately 70,000 in 1996 (Swift and
Holland 1998). After the dredging and filling, several surveys were
conducted and no gobies were detected, but they were found at Las
Flores, Cockleburr, and Hidden lagoons. The trestle repair work coupled
with the winter storms may have resulted in the extirpation of the goby
at San Mateo Creek. The consequences of population losses or
elimination of the San Mateo and San Onofre populations, which had
appeared to be two of the three most stable in the area, are very
serious because the effects could extend to other areas, contributing,
for example, to long term or permanent extirpation of the remaining
intermittent populations in the region (Hidden, Aliso, French and
Cockleburr creeks).
These examples described above illustrate serious adverse
population responses to earthmoving activities in and around creeks and
lagoons. The specific mechanism or mechanisms (e.g., changed
hydrological regime, siltation, water quality) leading to population
declines are not known, and it is also not known if gobies in the
Orange and San Diego counties distinct population segment respond
differently to environmental stresses than gobies to the north.
Tidewater gobies from Orange and San Diego counties are genetically
distinct and live in a very different physical and biotic environment
from those in more northerly habitats. It is possible that in this part
of the range, environmental stresses such as siltation or changed
hydrology affect gobies more severely than the same stresses to the
north. Or, environmental factors unique to southern California or
combinations of factors of which we are now currently unaware may be
leading to declines in disturbed areas occupied by Orange and San Diego
counties populations. Whatever the mechanisms, the recent loss or
serious reduction of the Santa Margarita River and San Onofre and San
Mateo lagoon populations, all of which have experienced human-caused
changes in hydrologic regime and earthmoving activities, suggests that,
in this part of the range, this kind of disturbance has serious
negative consequences for tidewater gobies. Depending on the
alternative alignment selected, the proposed Foothill Transportation
Corridor-South project could result in population effects similar to
those described above.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Populations North of Orange and San Diego Counties. Overutilization
is not known to be applicable; there is no change in this factor since
the species was listed in 1994.
Orange and San Diego Counties Population. Same as above.
C. Disease or Predation
Populations North of Orange and San Diego Counties. Disease was not
identified as a threat in the final listing rule, nor is it known to be
a threat at this time. Swenson (1995) reported finding cysts,
presumably of the digenean trematode (a flatworm or fluke (Cryptocotyle
lingua), and felt that the fluke could have been a factor in the
apparent population decline of tidewater gobies in Pescadero Lagoon in
1992 and 1993. However, gobies have persisted in the lagoon and
associated creek and marsh, at least through 1996 (J. Smith, pers.
comm. 1998). The fluke species also has been reported from fish in
Corcoran (Rodeo) Lagoon in Santa Cruz County (Swift et al. 1989), but
there is no indication of consequences for the tidewater goby
population there.
A large number of exotic species that have been perceived as
threats to the tidewater goby have been introduced into goby habitats.
In the final rule, the introduction of striped bass into the San
Francisco delta area was hypothesized to have caused the loss of
tidewater gobies in that habitat. However, no historic data exist to
test this hypothesis. As discussed in the background section, predation
by and competition with the introduced yellowfin, chameleon, and
shimofuri gobies exists. However, tidewater goby
[[Page 33823]]
populations north of Orange and San Diego counties are not particularly
vulnerable to these introduced fish. The centrarchid species largemouth
bass and green sunfish (Lepomis cyanellus) were identified in the final
listing rule as having caused the loss of at least two populations.
However, centrarchids are known to exist in many sites inhabited by
large populations of tidewater gobies (e.g., Santa Clara River, Las
Pulgas Creek, San Mateo Creek). Because of the range of salinity
tolerances of the tidewater goby and the more limited salinity
tolerances of many exotic species, and because tidewater goby
populations are sufficiently large and can repopulate from adjacent
streams, the threat of tidewater goby extirpation throughout its
habitat as a result of predation by exotic species appears minimal.
While exotic species forage on tidewater gobies, the current suite of
exotic fishes are not likely a serious threat to populations north of
Orange County at this time. Although African clawed frogs feed on
tidewater gobies (Lafferty and Page 1997), gobies are found in large
numbers in at least one habitat (Santa Clara River) occupied by the
frogs.
Orange and San Diego Counties Population. As described under Factor
A, above, it is not known if tidewater gobies in Orange and San Diego
counties respond differently to environmental stresses than gobies to
the north. Exotic fishes are thought to have played an important role
in population losses or declines in San Onofre Creek and the Santa
Margarita River. The predatory yellowfin goby, native to the inshore
marine waters of Japan and China, is established in most lagoons that
have or had gobies in Orange and San Diego counties. This and other
exotic species may or may not by themselves extirpate tidewater gobies
in Orange and San Diego counties, but when combined with other factors,
especially habitat disturbance (see Factor A, above), may pose a
serious ongoing threat to the Orange and San Diego counties distinct
population segment. In addition, only six populations remain and two of
the formerly largest have been seriously imperiled recently by human
activities (see Factor A, above). Therefore, threats such as exotic
predators, that prevent or contribute to significant reductions in
dispersal and recolonization of sites where gobies are temporarily
absent, could lead to the extinction of the entire Orange and San Diego
distinct population segment.
D. The Inadequacy of Existing Regulatory Mechanisms
Populations North of Orange and San Diego Counties. Inadequacies of
existing regulatory mechanisms were cited in the final listing rule as
a factor leading to the listing. This factor undoubtably contributed to
the loss of populations prior to the promulgation of environmental
regulations circa 1970. Currently, the review and permitting of
projects conducted by the ACOE under section 10 of the Rivers and
Harbors Appropriation Act of 1899 and section 404 of the Clean Water
Act (CWA) are unlikely to allow the extent of destruction and
modification of tidewater goby habitat that occurred prior to the
implementation of these regulations. Measures are often included as
standard measures in section 404 permits because other listed and
sensitive species (e.g., California red-legged frog (Rana aurora
draytoni), steelhead trout (Oncorhynchus mykiss), unarmored threespine
stickleback (Gasterosteus aculeatus williamsoni)) often occur in the
same locations as tidewater gobies. Examples of these measures include
eliminating or reducing siltation by silt fencing along project sites
and access roads, preventing sensitive species from entering project
areas, erecting coffer dams on either side of project sites, and timing
project activities to reduce impacts during the breeding season. Little
evidence exists to support the conclusion that existing regulatory
mechanisms inadequately protect the species or are contributing to
substantial or widespread population decline and loss in the northern
portion of the species' range (see Factor A, above).
Current regulations require that a project that may alter wetland
habitat be reviewed by and permitted through the ACOE and the
California Coastal Commission (CCC). During the review of projects,
avoidance of impacts (i.e., the prevention of habitat degradation
including that occupied by listed species) is the first consideration.
If wetlands will be altered, mitigation and/or compensation are
required (40 CFR Part 230, CCC 1994). Section 404 of the CWA and the
subsequent guidelines (40 CFR Part 230) for implementing that act
govern the discharge of materials into waters of the United States in
such a manner as to avoid or minimize impacts to (in part) human health
and welfare; aquatic life and wildlife; aquatic system diversity, and
productivity and stability; and they prohibit violation of state water
quality standards, Environmental Protection Agency toxic effluent
standards, the Act, and the Marine Protection, Research and Sanctuaries
Act. Projects within the California coastal zone come under the
provisions of the Federal Coastal Zone Management Act of 1990, and must
go through an environmental review process. As with projects falling
under section 404 of the CWA, the priorities are to avoid impacts, to
mitigate if impacts are unavoidable, and to provide compensation if
mitigation is infeasible (CCC 1994).
In most cases, current regulations generally do not require minimal
freshwater inflows into lagoons and estuaries in California. However,
in many cases, water inflows during the dry season probably are higher
than occurred historically due to wastewater treatment plant discharge
and urban and agricultural runoff. Although discharge of such effluents
was identified as an adverse factor in the final listing rule, and the
effects of such effluents have not been studied directly, many of the
habitats where such dry season inflows occur (e.g., Santa Ynez Lagoon,
Ventura Lagoon, Santa Clara Lagoon) support large populations of
tidewater gobies. A review of the Environmental Protection Agency's on-
line database AQUIRE found no contaminant data directly relating to
tidewater gobies. No published research has addressed contaminant
concentrations or effects in the tidewater goby. Little evidence exists
to support the conclusion that water diversions, groundwater
overdrafting and modifications in salinity regimes, or the discharge of
effluents are posing a significant threat to the ongoing existence of
the goby in the northern portion of its range, especially in today's
regulatory environment. Of the five populations extirpated due to
habitat destruction and modification since 1970, only the loss of the
Upper Morro Bay population possibly can be attributed to water
appropriation.
Orange and San Diego Counties Population. Despite the fact that the
previously cited regulatory mechanisms were in place, three of the
largest populations of tidewater goby (e.g., Santa Margarita River, and
San Onofre and San Mateo creeks) have been lost or nearly lost since
1993. The populations in San Onofre and San Mateo creeks were lost or
greatly diminished following single human-caused events occurring so
rapidly that existing regulatory processes failed to protect the
gobies. The small number (6) of extant populations in the Orange and
San Diego counties distinct population segment makes the loss of any
one population a greater cause for concern than in the northern portion
of the
[[Page 33824]]
range. With fewer extant populations, the likelihood of recolonization
of temporarily empty habitat is reduced, and the risk that all
populations will be extirpated due to drought or human factors is
greater.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Populations North of Orange and San Diego Counties. The
deterioration of coastal and riparian habitats mostly resulting from
drought was cited as the most significant natural factor adversely
affecting the tidewater goby in the final rule. At the time of listing,
California had experienced over 5 consecutive years of lower than
average rainfall. The stressful conditions brought on by the drought
were considered to be exacerbated by human-induced water reductions
(i.e., diversions of water from streams, excessive groundwater
withdrawals). The substantial increase in the numbers of populations
apparently extirpated and in the rates of decline of other populations
during the drought were the major impetus for listing the species.
However, since the end of the drought, 14 sites from which tidewater
gobies were believed to have been extirpated have been recolonized. The
recovery of nearly all populations and recolonization after the
prolonged drought demonstrated that recovery and recolonization of
habitats following natural events is probably a normal process for this
species. No information exists to indicate that the natural processes
are being significantly compromised by current regulatory mechanisms,
habitat use, or natural events. The survival and recovery of these
populations following a prolonged drought has alleviated the concern
that drought exacerbated by human-induced water reductions will result
in significant permanent population decline and loss.
The extent of habitat degradation and losses of the tidewater goby
from weather related phenomena, cited as threats in the final listing
rule, has been difficult to determine. However, flood events have been
shown to have no significant adverse effect on tidewater goby
populations. The flushing action of floods is probably the primary
mechanism for colonization of other habitats along the coast (Lafferty
et al. 1996, Swift et al. 1997).
Competition with introduced species also was identified as a
potential threat in the final listing rule. The competing species of
concern were the yellowfin goby and the chameleon goby. The shimofuri
goby is also found in some tidewater goby sites, exhibits dietary
overlap with the tidewater goby (Swenson 1995), and has been documented
to prey on tidewater gobies in the laboratory (Swenson and Matern
1995). The significance of these interactions in the wild remains
undocumented. To date no documented extirpation or population decline
can be attributed directly to these or other introduced competing
species. Lafferty and Page (1997) cite Brittan et al. (1970) and
McGinnis (1984) as evidence that the introduction of the yellowfin goby
into San Francisco Bay and the disappearance of tidewater gobies were
correlated. However, Brittan et al. (1970) do not discuss the
distribution of nor impacts on the tidewater goby. Lafferty and Page
(1997) cited Hubbs and Miller (1965) as evidence that killifish also
were involved in the loss of tidewater gobies from that region.
However, Lafferty and Page (1997) note that yellowfin gobies,
mosquitofish, and green sunfish coexist with tidewater gobies in at
least one location, the Santa Clara River.
Orange and San Diego Counties Population. Historically, natural
events such as high storm flows washed many fish, including tidewater
gobies, out of lagoons. These events ultimately may have benefitted
many native fishes, including tidewater gobies. High flows likely
reduced populations of predators, and gobies soon recolonized the
lagoons from adjacent populations. Unfortunately, the extirpation of
many historic tidewater goby populations from adjacent watersheds
requires the gobies to travel greater distances and from smaller source
populations. As a result, this natural recolonization is much more
difficult and uncertain.
Similarly, droughts may have temporarily reduced local tidewater
goby populations, but they soon recovered during wet years. However,
many of the larger tidewater goby populations in Orange and San Diego
counties have already been lost, and therefore, recolonization of
smaller intermittent lagoons following droughts appears much more
unlikely. Extended droughts, coupled with other physical alterations to
the lagoons threaten the tidewater goby in Orange and San Diego
counties.
Effects of the Rule
Finalization of this rule will change the portion of the range of
the tidewater goby listed as endangered from ``Entire'' to ``Orange and
San Diego counties'' in the List of Endangered and Threatened Wildlife.
Therefore, taking, interstate commerce, import and export of tidewater
gobies occurring outside of Orange and San Diego counties will no
longer be prohibited under the Act. In addition, Federal agencies will
no longer need to consult with the Service to ensure that any action
authorized, funded, or carried out by them is not likely to jeopardize
the continued existence of the tidewater goby outside of Orange and San
Diego counties.
The distinct population segment of the tidewater goby in Orange and
San Diego counties will remain an endangered species on the List of
Endangered and Threatened Wildlife. Federal agencies will need to
continue to consult with the Service to ensure that any action
authorized, funded, or carried out by them is not likely to jeopardize
the continued existence of the Orange and San Diego counties population
of tidewater goby.
Future Conservation Measures
Section 4(g) of the Act requires that all species that have been
delisted due to recovery be monitored for at least 5 years following
delisting. The tidewater goby populations north of Orange and San Diego
counties are proposed for delisting primarily because there have been
additional discoveries of tidewater goby populations since the original
listing and more complete information is now available. A monitoring
plan is not required for species delisted due to errors in or
insufficiency of the data on which the classification was based, but we
strongly encourage those parties involved in conducting surveys and
monitoring programs for tidewater gobies to continue their efforts and
forward the information to us.
Public Comments Solicited
We intend that any final action resulting from this proposal will
be as accurate and as effective as possible. Therefore, we solicit
comments or suggestions from the public, other concerned governmental
agencies, the scientific community, industry, or any other interested
party concerning this proposed rule. We particularly seek comments
concerning:
(1) Biological, commercial trade, or other relevant data concerning
any threat (or lack thereof) to this species;
(2) Additional information concerning the range, distribution, and
population size of this species; and
(3) Current or planned activities in the range of this species and
their possible impacts on this species.
The final decision on this proposal for the tidewater goby will
take into consideration the comments and any additional information we
receive, and such communications may lead to a final regulation that
differs from this proposal.
[[Page 33825]]
The Act provides for one or more public hearings on this proposal,
if requested. Requests must be received within 45 days of the date of
publication of this proposal. Such requests must be made in writing and
addressed to the office listed in the ADDRESSES section (above).
Required Determinations
Paperwork Reduction Act
This rule does not include any collections of information that
require approval by OMB under the Paperwork Reduction Act.
National Environmental Policy Act
We have determined that an Environmental Assessment or
Environmental Impact Statement, as defined under the authority of the
National Environmental Policy Act of 1969, need not be prepared in
connection with regulations adopted pursuant to section 4(a) of the
Endangered Species Act of 1973, as amended. We published a notice
outlining our reasons for this determination in the Federal Register on
October 25, 1983 (48 FR 49244).
References Cited
A complete list of all references cited herein is available upon
request from the Ventura Fish and Wildlife Office (see ADDRESSES
section).
Authors
The primary authors of this proposed rule are Ed Ballard and Grace
McLaughlin, Ventura Fish and Wildlife Office (805/644-1766), and Paul
Barrett, Carlsbad Fish and Wildlife Office (760/431-9440), U.S. Fish
and Wildlife Service.
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend part 17, subchapter B of Chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--[AMENDED]
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.
2. In Sec. 17.11(h), we propose to amend the table by revising the
entry for ``goby, tidewater'' under FISHES to read as follows:
Sec. 17.11 Endangered and threatened wildlife.
* * * * *
(h) * * *
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Species Vertebrate
-------------------------------------------------------- population where Critical Special
Historic range endangered or Status When listed habitat rules
Common name Scientific name threatened
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* * * * * * *
Fishes
* * * * * * *
Goby, tidewater.................. Eucyclogobius U.S.A. (CA)........ Orange and San E 527 NA NA
newberryi. Diego Counties
(U.S.A.-CA).
* * * * * * *
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Dated: May 28, 1999.
Jamie Rappaport Clark,
Director, Fish and Wildlife Service.
[FR Doc. 99-16030 Filed 6-23-99; 8:45 am]
BILLING CODE 4310-55-P